Ultra-HighPerformanceConcreteforSteelBeamEndRepairs
NESMEA2017ConferenceOctober17-18,2017| Hartford,CT
ArashE.Zaghi,PhD,PE,SEAssociateProfessor,UniversityofConnecticut
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Outline
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IntroductiontotheProblem
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America’sCrumblingInfrastructureASCE Report Card
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Problem– CorrosionDamage§ 15%ofstructurallydeficientbridgesexperienceheavycorrosiondamage
§ $8.3billionisspentannuallytorepairorreplacehighwaybridgeswithcorrosion
§ Girderbridgesmainlysufferfromcorrosionatthegirderends
§ Themaincauseofcorrosiondamageisdeicingchemicals
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ImpactontheStructuralCapacity
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CurrentRepairMethod
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OverviewofProposedRepairMethod
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RepairConcept
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LoadTransferMechanism
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qDefinitionofUHPC(FHWA2011)•Materialconsistingofoptimizedgranularconstituents•MaximumW/Cratioof0.25• Compressivestrengthoflargerthan22ksi• Enhanceddurabilityviadiscontinuousporestructure
qSelfconsolidatingwithoutvibrationqConstituents:cement,silicafume,silicapowder,sand,water,admixtures,steelfibers
UltraHighPerformanceConcrete
Component MassFraction(%)
PremixPowder 86.6
Water 5.1
Premia 150(HRWR1) 0.7
Optima100(HRWR2) 0.5
Turbocast (Accelerator) 0.9
SteelFibers 6.2
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UltraHighPerformanceConcrete
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UltraHighPerformanceConcrete
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Phase1:LargeScaleGirderTests
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TestedthreeW21x55Girders1. Undamaged: Baselinetomeasurecapacity.
2. Damaged:Webandflangereductiontosimulatecorrosiondamage.
3. Repaired:SamesectionreductionasDamaged,butwithUHPCrepair.
Loading Point
Test Beam
Phase1:Large-ScaleGirderTests
24”
12”
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RepairedFlexuralYielding
DamagedLocalizedWebBuckling
UndamagedGlobalWebBuckling
Phase1:Large-ScaleGirderTests
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Phase1:Large-ScaleGirderTests
Undamaged
Damaged
Repaired
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Phase2:DevelopmentofDesignGuide
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Phase2:ProjectOverview
InvestigationofstudcapacityinUHPC
Experimentalstudyoffull-scaleplategirders
Highfidelityfiniteelementmodelingandparametricstudies
Developmentofdesignguideandstandarddetailsforfieldapplication
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BehaviorofshearstudsinUHPCisdifferentthaninregularconcrete.
Phase2:StudCapacity
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Phase2:StudCapacity
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Typicalfailureofpush-outSpecimens
Phase2:StudCapacity
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Phase2:StudCapacity
Slip (mm)
Forc
e (k
ip/s
tud)
0 1 2 3 4 5 60
10
20
30
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D = 1/2 in (UHPC)D = 5/8 in (UHPC)D = 3/4 in (UHPC)D = 1/2 in (RSC)
UHPC f'c (ksi)
P u /
Asc
Fu
15 18 21 24 27 300.9
0.95
1
1.05
1.1
1.15
1.2
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Phase2:DurabilityTesting
PriortocastingUHPC,thewebofthesteelsectionwassubmergedfor60hourstoachievesurfacerust.
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Phase2:DurabilityTesting
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Phase2:DurabilityTesting
Slip (mm)
Forc
e (k
ip/s
tud)
0 1 2 3 4 5 60
4
8
12
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BenchmarkCorrosion1Corrosion2
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Phase2:LargeScaleTesting§ 54”-Deepplategirders
§ Testdifferentrepairgeometries:
• FullHeight
• HalfHeight
§ SimulateLiveLoad
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Phase2:LargeScaleTesting
Full-HeightRepairHalf-HeightRepairDamagedGirder
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Phase2:LargeScaleTesting
Full-HeightRepairDamagedGirderIntactGirder
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Phase2:LargeScaleTestingFiniteElementResults
Forcevs.Displacement
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RepairDesignExample
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q Constructedin1965
q Foursimplysupportedspans
q Rolledsteelmulti-girdersuperstructure
PilotBridgeRepairDesign
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PilotBridgeRepairDesign
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CurrentCondition
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Demand(kip)
#of½”Studs
#of⅝”Studs
LoadDesign
LiveLoadOnly 116 9 6
StrengthI(AASHTO) 301 22 15
CapacityDesign
Bearing 640 48 32
Shear 568 42 28
DesignNumberofShearStuds
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PlanView CrossSection ElevationView
SampleRepairDesign
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ForstudsembeddedinUHPC(Cao2017)
ADT=67,000vehiclesperday
N=147millioncycles(50yeardesignlife)
Allowablestressrange(basedonfatigue)=7.9ksi
Stressrangedemandunderfatiguetruck=7.0ksi
FatigueControl
8 log ∆𝜏 + log𝑁 = 22.1131
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SummaryandConclusions
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§ AnovelmethodhasbeendevelopedtorehabilitategirderswithcorrosiondamagebyattachingUHPCpanelstothegirderusingshearstuds.
§ ThecompositeactionoftheUHPCrepairintroducedasecondaryloadpaththroughtheshearstudstotransferbearingandshearforces.
§ TheUHPCrepairdemonstratedtheabilitytorestorebearingcapacitylostduetocorrosionover5timesthatofadamagedgirder.
§ Thisrepairoffersflexibilityregardinglocationandnumberofstudstotacklecomplexgeometriesundervariouslimitstates
SummaryandConclusion
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§ TheConnecticutDepartmentofTransportation
§MikeCulmoofCMEAssociates§ConnecticutTransportationInstituteofUCONN§GraduateStudents:KevinZmetra,KevinMcMullen,DominicKruszewskiandAlexandraHain
§ RabihBarakat § Bradley Overturf § RichardHanley§ TimothyFields § Anne-Marie McDonnell § Mary Baker
Acknowledgements
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RepairforSteelBridgeGirderswithCorrosionDamageUtilizingUHPC
Thankyou!
UltraHighPerformanceConcreteWorkshopJune28,2017| Albany,NewYork
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PDHQuestions
Whatisthecurrentcommonmethodforrepairingdeterioratedsteelgirderendregions?(singleanswer)a) Applypost-tensioningalonglengthofgirdertensionflange,
b) Weldorboltnewsteelplatesoverdeterioratedsteel,
c) Encasetheend10’ofeachdeterioratedgirderinconventionalconcrete,
d) SelectivelyapplysteelstudsandUHPCinandneardeterioratedregions.
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PDHQuestions
WhataresomeadvantagesofusingUHPCtorepairdeterioratedsteelgirderendregions?(multipleanswer)
a) UHPCcaneasilyflowintotightspaces,
b) UHPCcancarryhighertensileandcompressivestressesthanconventionalconcrete,
c) UHPCcostslessthanconventionalconcrete,
d) UHPCisfarmoredurablethanconventionalconcrete.
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PDHQuestions
TheUHPCgirderendrepairoffersflexibilityregardinglocationandnumberofstudstotacklecomplexgeometriesundervariouslimitstates?(True/False)
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PDHQuestions
ThefullscalestructuraltestingoftheUHPCrepairsolutiondemonstratedthatthelostbearingandshearcapacitycanoftenberecoveredinaproperlydetailedUHPCrepair?(True/False)